1. Rocks
Rocks are naturally occurring solid materials that make up the Earth's crust. They are made of one or more minerals and form in different ways.
🔄 Types of Rocks:
| Type | How It Forms | Examples |
|---|---|---|
| Igneous | When molten magma cools and solidifies | Granite, basalt |
| Sedimentary | From layers of sediment (sand, mud, fossils) | Limestone, sandstone |
| Metamorphic | From existing rocks changed by heat and pressure | Marble, gneiss |
💎 2. Minerals
Minerals are natural, solid, inorganic substances with a definite chemical composition and crystal structure. Rocks are made up of minerals.
🔹 Properties of Minerals:
-
Naturally formed
-
Solid and inorganic
-
Have a specific crystal shape
-
Differ in hardness, color, luster, and density
-
Many are valuable resources, such as gold or iron
🌟 Common Minerals:
-
Quartz – clear or white, very common
-
Gold – shiny, yellow, precious
-
Hematite – reddish-black, contains iron
-
Talc – softest mineral, used in powders
🌱 3. Soil
Soil is the top layer of Earth where plants grow. It is made from broken-down rocks mixed with water, air, and decayed plants and animals.
📌 How soil forms:
-
Rocks break down over time (weathering)
-
Organic material from plants/animals adds nutrients
-
Soil formation can take hundreds or thousands of years
🧱 Soil Layers (Horizons):
-
O Horizon – organic material like dead leaves (humus)
-
A Horizon – topsoil, rich in nutrients
-
B Horizon – subsoil, with minerals
-
C Horizon – weathered rock
-
Bedrock – solid rock underneath
🧪 Types of Soil:
| Type | Characteristics |
|---|---|
| Sandy | Drains quickly, low nutrients |
| Clay | Holds water well, dense and sticky |
| Loamy | Mix of sand, silt, and clay – very fertile |
| Peaty | Rich in organic material, holds moisture |
🌾 Why They Matter:
-
Rocks are used in construction (roads, buildings).
-
Minerals are essential for technology, industry, jewelry.
-
Soil is crucial for farming, forests, and ecosystems.
📚 Quick Summary:
| Term | Definition |
|---|---|
| Rock | A solid mixture of minerals found in nature |
| Mineral | A naturally occurring crystal with a specific chemical formula |
| Soil | A mixture of minerals, organic matter, water, and air |
✅ Final Thought:
Rocks, minerals, and soil are the foundation of life on Earth. They support:
-
🌍 The land we live on
-
🌱 The food we grow
-
🏗️ The materials we build with
Let’s respect and protect these valuable natural resources for future generations.